The invention relates to a shaft, in particular, a compensating shaft of a device for compensating forces of gravity and/or moments of inertia of a reciprocating piston internal combustion engine. The shaft is mounted so that it can rotate on one or more journals in a housing filled with a lubricating oil mist, wherein at least one of the journals projects radially past one or two shaft sections adjacent to these journals at least within one part of the periphery and wherein one or more radially outward extending ribs extend within the part of the periphery between the one or more journals and the one or two adjacent shaft sections.
Such a shaft is known from U.S. Pat. No. 6,305,339 B1 in which the shaft is formed as a compensating shaft of a mass-compensating drive known to someone skilled in the art in the field of reciprocating piston internal combustion engines. The compensating shaft proposed there has unbalanced masses arranged on both sides of a journal, while the journal projects significantly in the radial direction past the shaft sections adjacent to this journal within a part of the periphery that is diametrically opposite the unbalanced masses. For bracing the compensating shaft there are ribs that extend within the part of the periphery between the journal and the adjacent shaft sections.
As support means there is a sliding bearing shell arranged between the housing of the mass compensating gear and the journal as a hydrodynamic sliding bearing. A prerequisite for the construction of a sufficiently good load-bearing lubricating film in such a sliding bearing, however, is a defined supply of lubricating oil to the bearing point that leads, especially in the case of a typically cost-sensitive reciprocating piston internal combustion engine to undesired additional costs based on the boreholes and/or channels required for this purpose. Another disadvantageous property of the hydrodynamic sliding bearing results from the relationship between the viscosity of the lubricating oil and the friction power losses that can generally contribute especially at low temperatures and high viscosity lubricating oil to a considerable portion of the power losses of the reciprocating piston internal combustion engine or a machine driving the shaft.